1. Field of the Invention
The present invention relates generally to a continuity testing device. More specifically, the present invention is directed to a continuity testing device having a mechanism for detecting incomplete-fitting of a retainer of a connector.
2. Description of the Related Art
In a conventional continuity testing device used to test an electrical continuity of a connector of a wire harness, the connector is typically inserted into the continuity testing device along a vertical direction downward from an upward position, or along a horizontal direction from the front into the back of the continuity testing device.
One such continuity testing device is disclosed in Japanese Patent Application Publication No. 2007-85926 (hereinafter referred to as Conventional Art 1). For the continuity testing device according to Conventional Art 1, a connector is inserted into a connector insertion part of the continuity testing device downward from an upward position, then a continuity testing part located below the connector insertion part and having probe pins is moved upward towards the connector insertion part by driving a vertical air cylinder, thereby making the probe pins in contact with a terminal of an electric wire in the connector. In such manner, the electric wire connected to the terminal and an electric wire connected to the probe pins together form a closed circuit via a control unit, thereby detecting the electrical continuity.
Another example of a conventional continuity testing device is disclosed in Japanese Patent No. 3446675 (hereinafter referred to as Conventional Art 2). In this disclosure, a connector is provided with a retainer fitted to a recess formed on a side surface of the connector so as to securely fix a terminal within the connector. For this continuity testing device according to Conventional Art 2, the connector is inserted into a connector insertion part in a horizontal direction from the front, and the connector insertion part is provided with a detection projection. If the retainer is not completely fitted to the recess of the connector and thus protruding from the connector, the above-described detection projection will contact with the protruded retainer when the connector is inserted into the connector insertion part, thereby preventing the connector from being inserted further into the connector insertion part. In this way, the incomplete-fitting of the retainer is detected.
However, the continuity testing device according to Conventional Art 1 has a problem as described below. Referring to FIG. 10, a connector 74 to be tested for continuity is provided with a step-like connecter housing 71 having a recess (step) 72 located at an upper portion of the connector 74 adjacent to an electric wire 75 and a retainer 73 fitted in the recess. A reference sign 77 indicates a connector locking member. As can be seen from the illustration, the width of a connector insertion part 76 is defined by the size of an end 71a of the connector 74 which is larger than the size of the upper portion of the connecter 74 with the recess 72 and the retainer 73. Thus, it is difficult to provide to the connector insertion part 76 the above-described detection projection for detecting the incomplete-fitting of the retainer 73.
Furthermore, the continuity testing device according to Conventional Art 2 has a problem that, when a worker inserts the connector with the incompletely-fitted retainer into the connector insertion part, the worker hardly notices that the incompletely-fitted retainer is contacted with the detection projection. Thus, the worker continues to push the connector further into the connector insertion part, thereby lowering the accuracy of detection of the incompletely-fitted retainer, or possibly causing deformation or damage of the retainer.
Furthermore, there is required a separate continuity testing device for an exclusive use for the step-like shaped connector having the retainer fitted at the recess, causing an increase in cost.